Electric motor



March 23, 1954 R. c. BElTZ ELECTRIC MOTOR Original Filed Sept. 16, 1947INVE. NTOR C. EUTZ mar-man Patented Mar. 23, 1954 UNITED STATES PATENTOFFICE American Optical Company,

Sonthbridge,

Mass, a voluntary association of Massachusetts Original applicationSeptember 16, 1947, Serial No. 774,393. Divided and this applicationJune 10, 1952, Serial No. 292,694

.1947, now Patent No. 2,630,736, of which this application is adivision, relates to color analyzing apparatus and more particularly tospectrophotometric apparatus for providing substantially instantaneouslyand simultaneously visual indications of the several wave lengths andrespective intensities of light either transmitted by or reflected fromvarious materials while under examination. The apparatus disclosed inthe earlier filed application is so constructed and arranged that eventhough the material being examined may be of fixed or of changing colorcharacteristics, immediate analyzation of the material may be obtained,thus allowing, for example, its use in many commercial processes and thelike for indicating needed adjustments or corrections of the processWithout delay. Accordingly, more uniform maintenance of requiredstandards, high qualities and other desired properties in the goods ormaterials being produced may be had by use of the apparatus or device ofsaid earlier application.

Said earlier application, accordingly, comprises apparatus forilluminating and analyzing the color characteristics of eithertransparent or opaque materials in such a way that the component colorsof the material and their respective intensities may be individually andsimultaneously graphically presented upon a calibrated screen or thelike, so that same may be visually inspected, compared, traced,photographed or the like. The analyzing apparatus thereof comprisessimple and inexpensive means for so modifying the combined normalperformance characteristics of parts of the apparatus that fortransmitted .or reflected light there is produced upon the screen aluminous substantially straight line indicating substantially 100%transmission (or reflectance, as the case may be) for each of theseveral color components thereof. Thus, when material is inserted foranalysis, the intensities of the several color components thereof may beindividually and simultaneously indicated by per cent transmission orsome other well understood evaluating units.

Furthermore, the apparatus of said earlier application is arranged sothat the several wave lengths received from the material may beindicated in a horizontal direction upon the screen and the intensitiesor percentages of transmission (or reflectance) indicated in thevertical direction and in such proportions to calibrations on the screenas to accurately present thereon a Ill 5 a preferred form of thewell-known form of percentage transmission curve (or percentagereflectance curve). Said apparatus further comprises simple,lightweight, compact and inexpensive means which is operable upon aconventional source of alternating current and arranged to cause saidlight analyzing means to produce a wave motion in a definite phaserelation to and of like frequency with the current supply. Adjustablemeans is provided to cause this wave motion to have a definite wave formof such shape as to accurately produce upon a rectilinearly calibratedscreen or upon a progressivel; increasing calibrated screen(corresponding to the natural spacing of the spectrum colors) saidpercentage transmission and percentage reflectance curves. Thisadjustable means also allowing compensating for slight variations infunctioning of the apparatus. Said apparatus additionally includes meansfor removing or blanking out portions of the curve which normally wouldappear upon the screen, portions which would not be truly representativeof the color characteristics of the material under consideration. And,furthermore, readily operable means is provided for allowing adjustmentof the apparatus so as to modify its White light performance forslightly modifying end portions of the curve upon the screen to allowfor an accurate adjustment thereof into a straight line condition fortransmission or reflectance at all spectrum Wave lengths.

The present divisional application is directed to novelty in the detailsof the means for causing the li ht analyzing means to produce a wavernotion in definite phase relation to and of like frequency with thecurrent supply therefor and with the wave form thereof of such shape asto accurately produce upon a rectilinearly calibrated scale a percentagetransmission or a percentage reflectance curve. Said means is in theform'of a rapidly vibrating electric motor and electrical and mechanicalcomponents associated therewith which are of simple, light weight,compact and inexpensive construction and certain components of which arereadily adjustable for enabling said Wave motion to accurately match thesize and shape of said rectilinearly calibrated scale.

The invention will be better understood from the detailed descriptionwhich follows when taken in conjunction with the accompanying drawingsin which:

Fig. 1 shows a diagrammatic representation of apparatus of the presentinvention;

Fig. 2 is a diagrammatic representation of wave forms which may beproduced by the apparatus of Fig. l; and

Fig. 3 is an end view of an oscilloscope showing a rectilinear graphwhich may be placed thereon.

Referring to the drawings in detail and particularly Fig. 1, the numeralI6 indicates an entrant slit formed in a wall 11. The slit 16 may bebrightly lighted by a concentrated beam of substantially white light andthus serves as a source of illumination. A collimating lens system It ispositioned to focus on this slit and produce a beam of parallel light 23which impinges upon a prism 22. The prism 22 serves to refract anddisperse this beam 20 and a lens system 24 is so positioned relativethereto that it serves to focus the light as a spectrum at apredetermined plane 26. In this way the more or less white light emittedat the entrant slit I6 is broken up into its component colors. The partsof the apparatus just described diagrammatically represent a wellknownform of monochromator. A filter 21 or combination of filters to corrector modify, as desired, the light admitted by the slit may be inserted inthe optical system of the monochromator and preferably placed adjacentthe partition I I. If transparent material is inserted in the parallelbeam 23, as at the plane B, the spectrum at 28 will be modified.

Optically aligned with the lens system 24 of the monochromator andpositioned so as to be focused at the plane 26 is a lens system 28arranged to form an image of the spectrum at a distance therefrom. Forreasons which will appear presently it is desirous to align a reflectoror mirror 29 with the lens system 28 and arrange it in such angularrelation relative to this lens system that the image forming rays willbe directed to one side of the lens system 28 and re-image the spectrumat a focal plane 33. Positioned at this focal plane 30 is a partition 32provided with an exit slit 34 extending parallel to the slit [6 and thustransversely of the elongated direction of the spectrum. It will beclear that normally the light near the center of the spectral image atthe plane 30 will pass through slit 34 and since this slit is relativelynarrow such will be substantially monochromatic light. For reasons whichwill appear later it may be desirable that the center of the spectralimage normally fall slightly to one side or the other of the slit andaccordingly partition 32 may be arranged for movement laterally alongplane or the reflector supporting base 33 may be angled slightly to givethis off center condition.

A photosensitive device, such as a conventional electron multiplier 36may be positioned closely adjacent the exit slit 34 and so as to receivethe light rays passing through said slit and indicated by arrow 35 uponthe photosensitive cathode of the tube. This radiant energy received bythe photosensitive device produces a signal which, when amplified bymeans of known construction, may be impressed upon a set of verticallydisposed plates of an oscilloscope tube 43 (see Fig. 3). The amount ofvertical deflection of the cathode beam of the oscilloscope tube will bedependent upon the intensity of the radiant energy impinging upon thecathode of the photosensitive device. Since exit slit 34 is relativelynarrow in comparison with the total length of the spectrum at plane 30(in the neighborhood of mm. when spectrum equals mm.) only a relativelysmall portion of the spectrum will be transmitted through slit 34 at anyone time. It will be clear also that if the spectral image at the plane30 is moved relative to the slit 34 and the radiant energy at differentwave length will in turn impinge upon said cathode and electricalimpulses proportional thereto will deflect the cathode ray verticallyamounts equal to the intensities of the radiant energy received.

In order that the spectral image at plane 30 may be moved across exitslit 34 so that the intensities of the radiant energy at all portionsthereof may be successively sensed by the photosensitive device andaccordingly indicated graphically upon a fluorescent screen 46 of theoscilloscope tube, applicant has provided for the first surface mirroror reflector 29 a soft iron supporting and driving member 54 pivotedcentrally thereof so that it may be oscillated rapidly about an axis 56which is substantially parallel to slits l6 and 34 and sufficiently tosuccessively move all portions of the spectral image across slit 34. Themember 54 forms the moving armature part of a controllable electricmotor 58.. It has been found desirable to arrange motor 58 so as tofollow substantially the well-known sinusoidal wave characteristics of aconventional source of alternating current supply which is to beemployed for operating the apparatus. The alternating current supply isconnected to a primary 6UP of a transformer 60 and the secondary 608 ofthis transiormer is arranged to energize motor 58.

The secondary transformer terminal 6| is connected to a dry disc orequivalent rectifier 62 which is in turn connected to one terminal of anelectromagnet 64. The opposite terminal of this magnet 64 is connectedto one end of a variable resistance 66 which has its opposite endconnected to a terminal of a second electromagnet 68. The other terminalof the electromagnet 68 is connected to a rectifier l0 and thisrectifier is connected to the terminal 6 l. A variable arm of resistance66 is connected to a second resistance 12 and an adjustable armassociated therewith is connected to the opposite secondary terminal 13of transformer 60.

The motor circuit just described is such that during one half cycle ofthe alternating current supply a current is allowed to pass fromterminal 61 through rectifier 62, electromagnet 64, resistances 66 and12 to the other terminal 13. During the other half cycle the path of thecurrent in the opposite direction will be from terminal I3 throughresistances T2 and 66, electromagnet 68 and rectifier 10 to the oppositeterminal 6 l. Thus, during one half cycle the electromagnet 64 will beenergized so as to attract the mirror or reflector supporting anddriving member 54 and during the other half cycle electromagnet 68 willbe energized so as to attract the member. Thus, an oscillation will beset up in the member 54 and reflector 29 which will directly follow thealternating current frequency of the current supplied by the secondaryof transformer 63.

Biasing the member 54 into a normal or neutral position are a pair ofresilient members 14 which may be formed of sponge rubber or the like.Or, if desired, other suitable yieldable means such as light coil orleaf springs may be employed for urging member 54 toward said neutralposition. Thus pivotal movement of the member 54 about the axis 56 willcause the spectral image to be moved through an arc totalling a fewdegrees, with the result that all portions of the spectral image at theplane 33 will be caused to successively traverse slit 34 and allow theradiant energy, if any, of successive wave lengths to sue cessivelyimpinge upon the cathode of the photosensitive device 36. The combinedefiect of the attractive force of each electromagnet 64 or 68 as itbuilds up during each cycle and the compressive force of the resilientmember 14 which builds up progressively in opposition thereto is such asto produce a substantially uniform sinusoidal wave motion for reflector29.

Also connected. to the secondary terminals GI and 13 of the transformer60 is a D. C. or A. C. horizontal amplifier 15 which may be ofconventional construction and connected to a pair of horizontaldeflection plates of the oscilloscope tube 43 so as to cause the cathodebeam to travel transversely across the viewing screen thereof insynchronism with the frequency and phase of the alternating currentsupply received from transformerfiil. The cathode beam will be caused tomove across the tube in one direction as the mirror 29 is moved in onedirection and will be caused to move in the opposite direction as themirror moves in a reversed direction.

. It is desirable to be able to control or regulate the amplitude ofswing of the reflector 29 and thus the amount of travel of the spectralimage across and even beyond the exit slit 34, when desired, and forthis purpose the adjustable resistance 12 is provided. A decrease in theamount of resistance at 12 will increase the current throughelectromagnets 54 and 68 and thus the swing of the reflector 29 toopposite sides of its neutral position. The swing of the member 54,having an amplitude a and plotted against time for one full cycle isshown by the dotted line curve 76 in Fig. 2. Likewise, an increase inresistance of resistor 12 will decrease the swing. It will be clear thatwhen the swing is made to equal the length of the spectral image theimage will be scanned by a substantially true sinusoidal wave motion andthe successive wave lengths will be similarly plotted along thehorizontal upon the screen 46, of the oscilloscope tube 43. It should bekept in mind, however, that the spectral distribution resulting from anoptical retracting prism is not of a linear nature and, accordingly, thespacings between successive wave lengths are not uniform throughOut allparts of the resulting spectrum. For example, in a visible spectrumproduced by a refracting prism, the successive wave lengths toward thered end thereof are somewhat pinched together as compared to thosenearer the blue end of the spectrum.

In order to employ a substantially rectilinear scale in the horizontaldirection (along the abscissa) upon the viewing screen 56 and with thegraph 46' positioned thereon, instead of the sine wave spacings, thereflector 29 may be allowed to travel through a greater angular amountor amplitude for one half cycle than 'for the other half cycle. However,since the intervals during both half cycles are equal, it will beapparent that instantaneous rates of travel of the mirror during itslonger swing to one side will be greater than the correspondingratesduring its shorter swing to the other side, and this non-linearcondition,

I For this reason, theadjustableresistance 665is J provided in theconnection between the electromagnets. In this way, the current throughmagnet 64 may be increased or decreased at the expense of the currentthrough magnet 68 and thus the wave form of the oscillating reflector 52during one half cycle may be increased a desired amount, for example, asindicated at b and during the other half cycle decreased a substantiallyequal amount as indicated at b in Fig. 2. The resultant wave motion mayaccordingly be changed to a more desirable usable shape by moving theadjustable arm of resistor 66 one way or the other. Of course, themaximum amplitude of the reflector may be controlled or obtained by asubsequent readjustment of resistor 12. When the adjustable arm ofresistance 65 is in a center position the amount of swing will be thesame in both directions and no altering of the wave motion will beproduced thereby. Obviously, when such a condition is desirable theresistance 66 could as readily be omitted from the circuit andresistance 12 connected directly to the adjacent terminals of themagnets 64 and 68.

Thus the intensities of the various successive wave lengths transmittedthrough slit 34 may be sensed by photosensitive device 36 and theamplifled signal applied to the vertical deflection plates of theoscilloscope. These plates set up an electrostatic field which serves todeflect the cathode beam vertically in the tube 43 since the beam issimultaneously being moved horizontally across the screen 45 in onedirection by the horizontal amplifier 15 in. synchronism with themovement of reflector 29 the cathode beam will trace a path upon thescreen. As described in said copending application the horizontal travelof the cathode beam in the opposite direction is normally blank-ed out.In Fig, 3 is shown a graph 46' representing rectilinearly in thehorizontal direction (along the abscissa) wave lengths from 400 to 700millimicrons and in the vertical direction (along the ordinate)percentage of energy transmission. A dotted line 82 on the graphindicates the normal white light curve or luminous path of the beam whenno specimen is in the optical path as at B. The solid line 83, on theother hand, indicates a position to which the luminous line might besuppress-ed immediately upon the insertion of material, for example aplate of color'ed glass as at B in the system. For a betterunderstanding of the manner in which the intensity values are obtainedreference is made to 'copending application, Serial No. 774,393,previously referred to.

Reference has previously been made to the supporting base 33 for themotor 58. When this member is arranged for angular movement, preferablyabout an aXis coincident with the pivotal means 55, the motor andreflector 29 may be readily adjusted so as to place th center of thespectral'image normally off center a predetermined'amount relative tothe slit 34.

Thus. apreferred pcrtion of the useful half cycle of the wave motion,controlled by resistances 6B and E2, may be utilized. In such case theblanking means (not shown) may be readjusted so as to properly eliminateundesired parts of the curve from screen. 43.

While not shown in the drawing, it will be readily apparent from thepreceding description that instead of oscillating the reflector 29 bythe motor means 53 the wall 32 and exit slit 34 could as readily beoscillated by this motor means to effect a scanning of the spectralimage in :synohronism with the horizontal sweep 'of the: electron streamof: the oscilloscope: 2. The only material changes necessitated by sucha modified, construction wouldbe that the wall 3 2 be of relativelylightweight opaque material and the' cathode of electron multiplier beof such size that it will properly receive the light passing through themovable slit for all positions thereof. In such a construction thereflector 29 may remain in the optical system or may be omitted, inwhich case the exit slit will be located substantially in axialalignment with the lens System 28. The use of the reflector does,however,v allow a more compact construction. However, because theapparatus of Fig. 1 is of simpler construction, it is preferred.

It will clear that the motor means 58. and associated parts forproducing a readily controllable vibratory wave motion may be used inother devices wherein such a compact and ellicient assembly is desirablewithout departing from the spirit of the present invention.

Having described my invention, I claim:

1. An electric motor assembly comprisin a pair of stationaryelectromagnets, an oscillatable driving member, pivot means mountingsaid driving member for free pivotal movement relative to a fixed axis,said driving member having armature means disposed in adjacent spacedrelation to each electromagnet so as to be within the electromagneticfields thereof when said electromagnets: are energized, resilient meansso disposed relative to said driving member as to normally maintain saiddriving member in a neutral position when said electromagnets areunenergized, said resilient means being at such times unstressed butpositioned closely adjacent said driving member so as to be alternatelyprogressively stressed as said driving member is movedby eitherelectromagnet away from said neutral position, whereby eccentric loadingof said pivot means will be avoided, an electrical circuit for connectmeach electromagnet to a source of alternating current, and rectifyingmeans in each circuit arranged to allow said electromagnets to bealternately energized by said alternating current for moving saiddriving member away from said neutral position and for substantiallysinusoidally oscillating said driving member in synchronous relation tosaid alternating current.

2. An electric motor assembly comprising a pair of electromagnetsdisposed in relatively fixed side=-by-side relation, an oscillatabledriving member, pivot means mounting said driving member for freepivotal movementrelative to a relatively axis adjacent saidelectromagnets, said driving member having armature means at oppositesides of said fixed axis and disposed in adjacent spaced relation tosaid electromagnets respectively so as to be within the electromagneticfields thereof when said electromagnets are energized, resilient meansso disposed relative to said driving member as to normally maintain saiddriving member in a neutral position when said electromagnets areunenergized, said resilient means being at such times unstressed butpositioned closely adjacent said driving memher so as to be alternatelyprogressively compressed as said. driving member is moved by eitherelectromagnet away from said neutral position, whereby eccentric loadingof said pivot means will be avoided, an electrical circuit forconnecting each electromagnet to a source of alternating current, andrectifyin means in each circuit arranged to. allow said. electromagnetsvto be alternately energized by said .alternatingcurrent 'for movingsaid. driving member away from saidneutral position and forsubstantially sinusoidally oscillating said driving member insynchronous relation to said alternating current.

3. An electric motor assembly comprisin a pair of stationaryelectromagnets, an oscillatable driving member, pivot means mountingsaid driving member for free pivotal movement relative to a fixed axis,said driving member having armature means disposed inv adjacent spacedrelation to each electromagnet so as to'be within the'clectromagnetiefields thereof when said electromagnets are energized, resilient meansso disposed relative to said driving member as to normally maintain saiddriving member in a neutral position when said electromagn'ets areunenergized, said resilient means being at such times unstressed butpositioned closely adjacent said driving member so as to be alternatelyprogressively stressed as said driving member is moved by eitherelectromagnet away from said neutral position, whereby eccentric loadingof said pivot means will be avoided, an electrical circuit forconnecting each electrolnagnet to a source of alternating current,rectifying means in each circuit arranged to allow said electromagnetsto be alternately energized by said alternating current for moving saiddriving member away from said neutral position and for substantiallysinuscidally oscillatin said driving member in synchronousrelation tosaid alternating current, and adjustable means forming a part of each ofsaid circuits and arranged when in a predetermined. position to causesaiddriving member to effect a substantiallysinusoidalwave motion, andwhen adjusted to a difierent second position of adjustment to effect anincrease in the amplitude of said driving member during one-half cycleands, corresponding decrease in amplitude thereof during the other halfcycle period of operation thereof.

l. An electric motor assembly comprising a pair of electromagnetsdisposed in relatively fixed side-by-side relation, an oscillatable'driving member, pivot means mounting said driving member for freepivotal movement relative to a relatively fixed axis adjacent saidelectromagnets, said driving member having armature means at oppositesides of said fixed axis and disposed in adjacent spaced relation tosaidv electromagnets respectively so as to be within the electromagneticfields thereof when said electromagnets are energized, resilient meansso disposed relative to said drivingmember as to normally maintain saiddrivin member in a neutral position when said electromagnets areunenergized, said resilient means being at such times unstressed butpositioned closely adjacent said driving member so as to be alternatelyprogressively compressed as said driving member is moved by eitherelectromagnet away from said neutral position,. whereby eccentricloading'pf said pivot means will be avoided, an electrical circuit forconnecting each electromagnet to a source. of alternating current,rectifying means in each circuit arranged to allow said electromagnetsto be alternately energized by said alternating current for moving saiddriving member away from said neutral position and for substantiallysinusoidally oscillating said driving member in synchronous relation tosaid alternating current, and adjustable means forming a part of each ofsaid circuitsandarranged when in'a predetermined: position to cause saiddriving mem- 9 ber to effect a substantially sinusoidal wave motion, andwhen adjusted to a different second position of adjustment to eifect anincrease in the amplitude of said driving member during onehalf cycleand a corresponding decrease in amplitude thereof during the other halfcycle period of operation thereof.

5. An electric motor assembly comprising a pair of stationaryelectromagnets, an oscillatable drivin member, pivot means mounting saiddriving member for free pivotal movement relative to a fixed axis, saiddriving member having armature means disposed in adjacent spacedrelation to each electromagnet so as to be within the electromagneticfields thereof when said electromagnets are energized, resilient meansso disposed relative to said driving member as to normally maintain saiddriving member in a neutral position when said electromagnets areenergized, said resilient means being at such times unstressed butpositioned closely adjacent said driving member so as to be alternatelyprogressively stressed as said drivin member is moved by eitherelectromagnet away from said neutral position, whereby eccentric loadingof said pivot means will be avoided, an electrical circuit forconnecting each electromagnet to a source of alternating current,rectifyin means in each circuit arranged to allow said electromagnet tobe alternately energized by said alternating current for moving saiddriving member away from said neutral position and for substantiallysinusoidally oscillating said drivin member in synchronous relation tosaid alternating current, adjustable resistance means connected inseries with both of said circuits so as to efiect when adjusted anincrease or a decrease in the amplitude of drivin member during eachhalf cycle period of operation thereof, and additional adjustableresistance means forming a part of each or said circuits and arrangedwhen in a predetermined position of adjustment to cause said drivingmember to effect substantially equal amplitudes during both of said halfcycle periods, and when adjusted to a different position of adjustmentto efiect an increase in the amplitude of said driving member during onehalf cycle and a corresponding decrease in amplitude thereof during theother half cycle period of operation thereof.

6. An electric motor assembly comprising a pair of electromagnetsdisposed in relatively fixed side-by-side relation, an oscillatabledriving member, pivot means mounting said driving 10 member for freepivotal movement relative to a relatively fixed axis adjacent saidelectromagnets, said driving member having armature means at oppositesides of said fixed axis and disposed in adjacent spaced relation tosaid electromagnets respectively so as to be within the electromagneticfields thereof when said electromagnets are energized, resilient meansso disposed relative to said driving member as to normally maintain saiddrivin member in a neutral position when said electromagnets areunenergized, said resilient means being at such times unstressed butpositioned closely adjacent said driving member so as to be alternatelyprogressively compressed as said driving member is moved by eitherelectromagnet away from said neutral position, whereby eccentric loadingof said pivot means will be avoided, an electrical circuit for connectineach electromagnet to a source of alternating current, rectifying meansin each circuit arranged to allow said electromagnets to be alternatelyenergized by said alternating current for movin said driving member awayfrom said neutral position and for substantially sinusoidallyoscillating said driving member in synchronous relation to saidalternatin current, adjustable resistance means connected in series withboth of said circuits so as to effect When adjusted an increase or adecrease in the amplitude of drivin member during each half cycle periodof operation thereof, and additional adjustable resistance means forminga part of each of said circuits and arranged when in a pre determinedposition of adjustment to cause said driving member to eifectsubstantially equal amplitudes durin both of said half cycle periods,and when adjusted to a different position of adjustment to effect anincrease in the amplitude of said driving member during one half cycleand a corresponding decrease in amplitude thereof during the other halfcycle period of operation thereof.

RICHARD C. BEITZ.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,860,492 Butler May 31, 1932 1,954,029 Stansbury Apr. 10,1934 FOREIGN PATENTS Number Country Date 639,997 Germany Dec. 21, 1936

